Method and apparatus for cooling hot materials by gas



Sept. 22, .1959 PETERSEN 2,905,395

METHOD AND APPARATUS FOR COOLING HOT MATERIALS BY GAS Original Filed Dec. 23, 1954 I U o N I a J 3 8 81' INVENTOR. Aas $2. I

ATTO NEYS United States Patent "li/IETHOD AND' APPARA' TUSFOR C'OULlNGHGT MATERIALS BY GAS L'ouis Petersen, *Rye,"N.Y., assignor to FfiLfiSmidth 8:

Co., New -ork,aN. Y,,taq.corporationr of= New Jersey This invention relates to the cooling of hot materials, such as are produced in a burning operation in a kiln, and is concerned more particularly with a novel method for efiecting rapid and uniform cooling of such materials by means of gases and with apparatus for the practice of the method. The method and apparatus of the invention may be employed in the cooling of various materials but olfer especial advantages in the treatment of cement clinker produced in a rotary kiln. That application of the invention will, accordingly, be illustrated and described in detail for purposes of explanation.

Cement clinker discharged from a kiln is of high temperature, which may be of the order of 2000 F., and must be cooled before it can be subjected to later operations. Such cooling may be effected by passing air through a bed of the clinker, but, if the clinker contains lumps of substantial size as well as the usual relatively small pieces, it is difficult to cool the lumps in an apparatus, which is satisfactory for the cooling of the small pieces.

The present invention is directed to the provision of a method and apparatus, by the use of which a hot material made up of pieces varying considerably in size can be rapidly cooled. In the cooling operation of the invention, the material is first partially cooled by contact with a gas and thereafter the coarse or oversize pieces are separated from the remaining fine pieces and crushed. The crushed product is then combined with the fine pieces and the combined material is carried along in suspension in a gas stream to a separator, in which the solids are separated from the gas. In its travel with the gas stream, the material gives up heat to the gas and, since the larger pieces of the material have been broken up by the crusher, the material may be rapidly and uniformly cooled.

For a better understanding of the invention, reference may be made to the accompanying drawing, which shows one form of apparatus for practicing the method of the invention.

The kiln installation of the invention includes a kiln 10, on the lower end of which is mounted a recuperator 11. Clinker discharging from the kiln passes through the recuperator and is partially cooled by air, the air then entering the kiln for use as secondary air of combustion. Such recuperators are well known and a typical recuperator suitable for the purpose is that illustrated in Narsted and Lindhard Patent 2,268,296, issued December 30, 1941. Such a recuperator has a clinker discharge section 12 and it is surrounded by a wind box 13, through which air is admitted to its interior.

The recuperator discharge section 12 enters a kiln hood 14, through which a burner 15 projects, and the hood has a bottom opening, from which a chamber 16 extends in a generally downward direction. A screen 17 leads downwardly at an incline from the interior of hood 14 into chamber 16 and a crusher 18 is mounted in the chamber at the lower end of the screen. Below the crusher, the chamber contains a weighted flap gate 19 pivoted in the chamber 17, which bears against crushed clinker ttravelingflown by gravity :through chamber 16 and :opens when :a suiiicient weight o'f :crushed *elir'rker huilds up in the :cham-ber. 'The -lower -en'd of chamber 51:6 is econnecterl ithrough a :suitiblefitting to a riser pipe :21 :leadingnpwar'dlwto the inlet: of t a cyclone se'pa- :rator An :air --intake 23 is :connected {to =the Elower ;=tendiof fitting20. flihe:gas outlet ef =separator 22 is c'o'n rneete'dthyamip'e 24 tocthe inlet of a fan 25, whilem discharge pipe 26 leads afromthe solids-outlet of the' sepa- 51531011 'sAipipe 27:containing a damper127a1leads from the ges :onthetaof therseparatorrtozwindbox i1 5and thusjsuppl i'e's air for ccooling ithe clinker wvithin :the zrecuperator. branch pipe 28 containing a damper 28a leads from pipe 27 and delivers air to be used as primary air of combustion. Another branch 29 containing a damper 29a leads from pipe 27 and may be employed to discharge air to the atmosphere.

In the practice of the invention, the clinker issuing from kiln 10 enters the recuperator 11 where it is partially cooled by air delivered by fan 25. The clinker leaving the recuperator is discharged upon screen 17 and thereby separated into a fine fraction and a coarse fraction. The coarse fraction moves along the screen to the crusher 18 where it is broken up, while the fine fraction passing through the screen by-passes the crusher. The fine and crushed fractions are combined below the crusher and enter the fitting 20 where the material is picked up in the air stream traveling upward through pipe 21. The material receives a second stage of cooling while moving in suspension to the separator 22 where the clinker is separated from the air and the latter drawn oil for use in the recuperator and for primary air of combustion.

The new method and apparatus are advantageous, in that hot material, comprising particles of various sizes, is partially cooled and separated into fine and coarse fractions before crushing the coarse fraction to a size suitable to be carried along in suspension in a stream of cool gas, along with the fine fraction. The steps of partial cooling and separating prevent overheating of the crushing rolls and permit the coarse fraction to be crushed at an advantageous stage in the operating cycle to facilitate rapid cooling of the total body of hot material.

This application is a division of my copending application, Ser. No. 477,341, filed December 23, 1954, for Method And Apparatus For Cooling Materials By Gas, now Patent No. 2,841,384.

I claim:

1. A method of cooling hot material of diflerent particle sizes, which comprises partially cooling the mate rial by advancing the material and passing a cool gas in contact therewith, separating the partially cooled material into coarse and fine fractions, crushing the coarse fraction, combining the crushed product with the fine fraction, introducing the combined material into a flowing gas stream, carrying the combined material in sus-, pension in the gas stream until the desired cooling of the material is completed, and separating the cooled material from the gas stream.

2. The method of claim 1, in which the partially cooled material is separated by being passed along an inclined screen, the coarse fraction is taken from the top of the screen and crushed, the fine fraction flows downward below the screen, and the crushed product and fine fraction are combined by being caused to flow together toward the gas stream.

3. The method of claim 1, in which the gas stream flows vertically upward, and the material is carried upward with the stream.

4. Apparatus for cooling hot material of diiferent particle sizes, which comprises means for receiving the hot material in a relatively continuous stream, means for par tially cooling the hot material by causing gas to fiow' in contact therewith, means for separating the partially cooled material into coarse and fine fractions, means for crushing the coarse fraction, means for flowing the fine 'fraction in by-passing'relation to the crushing means,

' means for. combining the by-passed fine fraction with the crushed product, means formaintaining a'flowing gas I stream, means for introducing the combined crushed prodalong in suspension therewith and cooled, the stream being of such length that the material suspended therein is cooled to the desired extent, and means for separating the cooled material from the gas stream.

net and fine fraction into the gasstream to be carried 5. The apparatus of claim 4, in which the separating -mean's comprises an inclined screen positioned to receive partially cooled material, the crushing means is positioned at the lower end of the screen for receiving coarse macrushed product and fine fraction pass to, reach the gas stream.

References Cited in the file of this patent UNITED STATES PATENTS 2,375,487 Newhouse May 8, 1945 2,446,175 Gerber Aug. 3, 1948 2,506,455 Jackson .L. May 2, .1950 2,595,117 Ahlmann Apr. 29, 1952 2,639,862 Watts e May 26, 1953 

